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CORVALLIS - Oregon State University agricultural researchers have published the first of what is expected to be a yearly report for growers on the biology and control of the septoria diseases.

"The Biology and Control of the Septoria Diseases of Winter Wheat in Western Oregon," (Special Report 960) was recently published by the OSU Agricultural Experiment Station.

"We decided there was a need for some kind of publication that would help growers make decisions about the septoria diseases of winter wheat," said Julie DiLeone, faculty research assistant in OSU's Department of Botany and Plant Pathology and one of the authors of the report.

"Every year we get calls from extension agents who have questions from growers," she said. "We decided to provide them with this information every year so that they'd have it for reference.

"This new publication, will help the farmer evaluate if there is enough disease in a particular season to warrant a fungicide application," she added.

The report is now on file with county agents of the OSU Extension office in western Oregon counties.

Septoria has become more of a problem on wheat crops in the Willamette Valley during the last several years, explained DiLeone. Both of the fungi that cause the septoria diseases can cause significant yield loss on susceptible cultivars. One of the septoria fungi infects and discolors the seed head, making it difficult for growers to meet high quality standards. Growers may be forced to sell the wheat at a lower price for livestock feed instead of for human consumption.

"The environmental conditions in the Willamette Valley are very favorable for the septoria diseases," DiLeone said. "A rainy year will mean the fungus will most likely thrive."

The fungi that cause the septoria diseases survive between wheat seasons on debris and volunteer wheat. Beginning in the fall, spores are produced and are blown by the wind onto the wheat crop. These spores cause the first infections of the wheat crop.

"Once these fungi infect the wheat plant, large numbers of additional spores are produced and splashed by rain to other leaves and plants," she said. "This causes the disease to spread with every rainfall. The timing of the fungicide application is crucial to reduce that secondary spread and prevent the fungus from moving up the plant."

According to DiLeone, these fungicide applications are expensive. It is a difficult decision for growers to apply it, when they are not sure if there will actually be a problem with septoria that season.

"The Biology and Control of the Septoria Diseases of Winter Wheat in Western Oregon" (SR 960) is available for reading at your local county office of the OSU Extension Service. The report was written by DiLeone; Stella Coakley, department head; Chris Mundt, associate professor in botany and plant pathology; and Russ Karow, associate professor of crop and soil science at OSU. For additional information, contact Karow, Extension cereal specialist, Department of Crop and Soil Science, OSU, Crop Science Bldg., Room 107, Corvallis, OR 97331-3002.